Often referred to as the powerhouses of the cell, mitochondria provide the energy that powers nearly every cellular process. This essay by John Ross describes in detail the structures and functions of these amazing organelles.

In this interactive activity adapted for grades 3–5 from Annenberg Learner’s Teaching Math Grades 6–8, use virtual Cuisenaire® Rods to represent fractions and to perform operations with fractions.

This Wide Angle video provides an introduction to the four personable female stars of Sweet Talk, a popular television show in the Arab world.

In this interactive activity from ChemThink, learn about covalent molecules and how the VSEPR theory predicts the shapes of covalently-bonded molecules.

This video from Nature features the start of the monarch butterflyŒë_í_Œ_ northward trek.

This video segment follows neurophysiologist Allen Counter as he studies an epidemic of hearing loss in Moriussaq, Greenland, one of the quietest places on Earth. Footage from NOVA: "Mystery of the Senses: Hearing."

This video segment adapted from NOVA relates the dramatic story of vulcanologists trying to predict the timing of the cataclysmic eruption of Mount Pinatubo in the Philippines.

This interactive activity adapted from A Science Odyssey Web site helps you visualize different types of plate tectonic activity and shows the impact this activity has on Earth's surface.

In this lesson designed to enhance literacy skills, students examine how to multiply fractions by whole numbers in the context of a recipe.

In this video segment from Religion & Ethics Newsweekly, learn about the daily prayer rituals of the Muslim faith and their significance in the life of a Muslim living in America.

Join a group of middle-school students on a visit to a laboratory at the Massachusetts Institute of Technology, where they experiment with "mystery mud" and learn about the relationships between magnetism, particle motion, and changes in the state of matter.

In this video adapted from NOVA scienceNOW, find out about the discovery of a new building material, the carbon nanotube, whose physical properties could theoretically enable the creation of a 22,000-mile elevator to space.

In this video segment adapted from Haskell Indian Nations University, student filmmakers explain why it is important to them to make a video about climate change.

In this video from WOSU Columbus, learn about the types of communities of plants, animals, birds and fish that abound in wetlands.

In this video segment adapted from Navajo Technical College, meet two members of the Navajo Nation, one Elder and one scientist, as they share their observations about how precipitation has changed since they were children.

In this video segment from WILD TV, a guide describes how to camouflage a personŒë_í_Œ_ body to avoid being detected in the wilderness.

The NFL kicked off its new season last night with new safety measures that may lessen the chance of injury for players. Video, teacher page, and student handout included.

Informational text piece discussing how new NFL rules are making football safer. Student handout and video. High interest.

In this lesson designed to enhance literacy skills, an early astronaut's experiences teach students that Newton's third law of motion—for every action, there is an equal and opposite reaction—applies both on Earth and in outer space.

In this video segment adapted from NOVA, NASA learns hard lessons from the first American attempt to do work while "walking" in space. The video also explores Newton's third law of motion.